CpG ODNs accelerate GVHD mortality. (A-C) CpG ODNs were given intraperitoneally to cohorts of mice on d0, d7, d14, d21, and d28 (100 μg/dose). CpG indicates CpG treatment. (A) Lethally irradiated B10.BR mice were given B6 BM and 5 × 10⁶ or 25 × 10⁶ splenocytes (eg, 5S = 5 × 10⁶, 25S = 25 × 10⁶ splenocytes). n = 8/group, P ≤ .036. (B) Lethally irradiated B6 mice were given BALB/c BM and 5 × 10⁶ or 15 × 10⁶ splenocytes. n = 16 to 24 per group, pool of 2 to 3 experiments; P ≤ .009. (C) Nonirradiated, NK cell–depleted BALB/c SCID mice were given 10⁶ or 3 × 10⁶ purified B6 T cells; n = 8/group, P < .05.